So I too like the grain bill. I have been making great apa's and ipa's with about 10% oats (in this case wheat is perfect) and about 10% carapils. The only thing I would do - and this is me, like i said the bill already looks good- is a full pound of the carapils and wheat along with the other grains you already have listed
For the hops: CTZ is a great bittering hop and with your grist maybe .75 oz would be a great amount. That should give you an IBU of about 40 using an estimated OG as 1.050 and if the AA of the CTZ is 16.3%.
the rest of those bright hops you have there, I wouldn't add another dose of hops until flameout. I must admit, I have never used galaxy and have no idea how powerful they are. I have read great things and know Citra is a substitute. I use lots of Citra.
Anyway you add those hops at flameout say a half ounce each, let them sit for about 30 minutes while stirring every 5 minutes. Then cool your wort down to like 170-180 and throw the rest in, including that .25 ounce of CTZ you have left over. Let it sit, stir every 5 minutes for another 30 minutes. Don't worry if the temp drops below 170. Just keep keep letting them steep. This whirlpool will add tremendous flavor and aroma to your beer. It also adds bitterness so although the -calculated- IBUs are low, the addition of all of those whirlpool hops adds bitterness. I just don't know how to calculate the finished product. My last 5 IPAs have been done this way and each one is better than the last. My last three beers have been with 20% adjunct/carapils added as I suggested above.
After that whole hour of steeping those hops, cool as usual and pitch.
Rack when completed fermenting and add between 4 and 5 ounces of your dry hop combo. Yes, 4-5 ounces. Sure it's expensive but if you like hoppy beers those dry hops will impart an aroma which adds to the perceived flavor. let those sit for another 7-10 days at about 65*.
I think with that grain bill and complete whirlpool after only 1 bittering addition and those extra 4-5 ounces of dry hops, your finished product will be a light colored and bright smelling/tasting fantastic beer.
Cheers and let us know how it turns out and what you decide to do.
